1. The Field of the Invention
The present invention relates to cutter domes for use with a reclaim system within a storage vessel.
2. The Relevant Technology
Silos are used for storing bulk material such as grains or powders. The bulk material is typically deposited into the silo through an opening formed at the top of the silo and is removed from the silo through an outlet centrally formed on the floor the silo. Bottom reclaim systems are often mounted on the floor of the silo for controlling movement of the bulk material to the outlet. The bottom reclaim system includes a base mounted adjacent to the outlet and an auger that outwardly projects from the base. The auger rotates about a central longitudinal axis thereof so as to inwardly draw the bulk material from the perimeter of the floor to the outlet. Furthermore, as the auger rotates about its longitudinal axis, the auger also revolves around the central outlet on the silo floor. As a result, the auger draws bulk material to the outlet from all areas on the silo floor.
It is often desirable to have a first-in-first-out (FIFO) inventory control of the bulk material within the silo. This ensures that a portion of the bulk material does not stagnate within the silo. In cases where FIFO is important, it is desirable to have the outlet covered so that the bulk material directly above the outlet does not free flow into the outlet, thereby precluding FIFO inventory control. A solution to this problem has been to position a dome on the floor of the silo that covers the outlet and the base of the reclaim system. The dome has a cylindrical sidewall and a conical roof An opening is formed on the sidewall of the dome through which the auger passes. The auger draws the bulk material through the opening and to the outlet in a controlled manner. The dome prevents the free-flow of bulk material into the outlet, thereby helping to ensure the FIFO storage of the bulk material.
The dome, however, introduces other problems. For example, even though the roof of the dome is conical, the bulk material can post on the roof of the dome. In posting, a significant portion of the entire amount of bulk material within the silo bears its load on a localized region. Specifically, the bulk material can vertically stack on the roof of the dome in a cohesive structure that remains stationary as opposed to flowing out toward the auger. In turn, this stacked bulk material above the roof can bridge outward until it eventually reaches the interior surface of the silo. In this scenario, large cavities can be produced within the silo as the reclaimer removes the freely movable bulk material from below the bridging bulk material.
As a result of the posting of the bulk material on the dome, the dome and reclaimer can be subject to tremendous point-loading caused by the bulk material. That is, whereas the entire weight of the bulk material is typically uniformly carried over the entire floor of the silo, posting of the bulk material causes the weight of a large percentage of the bulk material to be concentrated on the dome. This point loading of the bulk material can result in failure of the dome and/or reclaimer. Furthermore, the stacking and bridging of the bulk material and the resulting formation of cavities precludes efficient operation of the reclaimer and prevents FIFO flow of bulk material within the silo. In some situations, movement of the bulk material within the silo can be completely stopped. In turn, disrupting the stacked bulk material within the silo to restore proper flow of the bulk material can be time consuming and dangerous.